1. Field of the Invention
This invention relates to a method for the production of an epoxy compound. More particularly, this invention relates to a method which comprises epoxidizing an ethylenic compound with hydrogen peroxide thereby producing a corresponding epoxy compound and hydroxy iminodisuccinic acid with a high yield without inducing coloration.
2. Description of the Prior Art
The method for producing an epoxy compound by epoxidizing a corresponding ethylenic compound with hydrogen peroxide has been known for a long time. The catalyst, reaction condition, etc. to be used for this reaction are being studied with great enthusiasm. Numerous patents and documents have already issued from the researches.
As one way of producing epoxysuccinic acid by epoxidizing maleic anhydride with hydrogen peroxide, the present inventors have proposed a method for obtaining epoxysuccinates with a high yield by using two different reaction temperatures and thereby economizing the epoxidizing catalyst (JP-A-04-290879).
No reports have been published concerning the study on the material for the reaction vessel to be used in the epoxidation of maleic anhydride with hydrogen peroxide. The fact that glass, stainless steel, aluminum, etc. are usable as materials for the vessels to be used in handling hydrogen peroxide has been barely known.
The present inventors, in order to produce epoxysuccinic acid on a commercial scale, have tried the epoxidation with a reaction vessel made of stainless steel which is popularly used as an industrial grade material. They have consequently found that this reaction vessel entails the problem of lowering the yield of epoxysuccinic acid relative to maleic anhydride and inducing the produced reaction solution to undergo coloration. After a further study on this problem, they have found that part of hydrogen peroxide gasifies during the course of the reaction, contacts with the surface of stainless steel in the gaseous phase part of the reaction vessel, and undergoes the decomposition caused by the action of stainless steel. Their study has boiled down to a conclusion that when hydrogen peroxide is supplied in an equimolar amount to maleic anhydride, the yield of epoxysuccinic acid relative to maleic anhydride is ultimately lowered because of the decomposition of hydrogen peroxide. Though the cause for the coloration of epoxysuccinic acid has not yet been elucidated, the coloration may be logically explained by a supposition that the decomposition of hydrogen peroxide entrains a secondary reaction of some form or other and the by-product arising from this secondary reaction persists in epoxysuccinic acid and imparts a color thereto.
The lowered yield induces a decrease in productivity and the coloration seriously impairs the salability of the product, both of which prove unfavorable.
This invention, concerning the production of an epoxy compound by the epoxidation of a corresponding ethylenic compound with hydrogen peroxide in a reaction vessel made of a metal, is aimed at solving such problems as the decomposition of hydrogen peroxide which occurs during the course of the reaction and the degradation of yield and the coloration of the epoxy compound which ensue from the decomposition and consequently enabling the epoxy compound to be produced with a high yield without inducing coloration.
Further, this invention is aimed at producing hydroxy iminodisuccinic acid of high quality without inducing coloration.